Repeatable block producing a non-uniform routing architecture in a field programmable gate array having segmented tracks

ABSTRACT

A repeatable non-uniform segmented routing architecture in a field programmable gate array comprising: a repeatable block of routing tracks, the routing tracks grouped into sets of routing tracks, each set having a first routing track in a first track position, a second routing track in a last track position, a programmable element, and a direct address device for programming the programmable element; wherein at least one of the routing tracks is segmented into non-uniform lengths by the programmable element and the second routing track crosses-over to the first track position in a region adjacent to an edge of the repeatable block; and wherein a first plurality of the routing track sets proceed in a horizontal direction and a second plurality of the routing track sets proceed in a vertical direction.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of co-pending U.S. patent applicationSer. No. 11/426,541, filed on Jun. 26, 2006, which is continuation ofU.S. patent application Ser. No. 11/120,509, filed May 2, 2005, nowissued as U.S. Pat. No. 7,075,334, which is a continuation of U.S.patent application Ser. No. 10/330,672, filed Dec. 27, 2002, issued asU.S. Pat. No. 6,891,396, which are hereby incorporated by reference asif set forth herein.

BACKGROUND OF THE SYSTEM

1. Field of the System

The present system relates to field programmable gate array (FPGA)devices. More specifically, the system relates to a routing architecturebetween logic modules in an FPGA having segmented tracks that can bestepped and repeated such that the segment block only has to be designedonce.

2. Background

FPGAs are known in the art. An FPGA comprises any number of logicmodules, an interconnect routing architecture and programmable elementsthat may be programmed to selectively interconnect the logic modules toone another and to define the functions of the logic modules. An FPGA isan array of uncommitted gates with uncommitted wiring channels. Toimplement a particular circuit function, the circuit is mapped into anarray and the wiring channels' appropriate connections are programmed toimplement the necessary wiring connections that form the user circuit.

A field programmable gate array circuit can be programmed to implementvirtually any set of functions. Input signals are processed by theprogrammed circuit to produce the desired set of outputs. Such inputsflow from a user's system, through input buffers and through thecircuit, and finally back out the user's system via output buffers.

An FPGA core tile may be employed as a stand-alone FPGA, repeated in arectangular array of core tiles, or included with other devices in asystem-on-a-chip (SOC). The core FPGA tile may include an array of logicmodules and input/output modules. An FPGA core tile may also includeother components such as read only memory (ROM) modules. Horizontal andvertical routing channels provide interconnections between the variouscomponents within an FPGA core tile. Programmable connections areprovided by programmable elements between the routing resources.

The programmable elements in an FPGA can be either one-time programmableor re-programmable. Re-programmable elements used in FPGA technologiesmay comprise transistors or other re-programmable elements as is wellknown to those of ordinary skill in the art. One-time programmableelements used in FPGA technologies may comprise antifuse devices.

Horizontal and vertical routing channels are comprised of a varyingnumber of routing tracks. It is often desirable to segment routingtracks. Segmented routing tracks increase the speed and performance ofintegrated circuits. For instance, if a particular integrated circuithas long routing tracks due to the size of the device, the time it takesfor a signal to travel along the routing tracks may be long due toincreased resistance and capacitive loading on the tracks. This isespecially true in antifuse FPGAs. Unprogrammed antifuses along therouting tracks act as small capacitors, and thus decrease theperformance and speed in antifuse FPGAs. Segmented tracks also reducedie area. Using an entire routing track to route a signal when only aportion of the track is required tends to waste die area.

It is even more desirable if the segmentation of the routing tracks isnon-uniform. A non-uniform segmented channel array provides a variety oftrack lengths, and thus is more flexible and faster than a device havinga uniform segmented channel array. Segmented tracks also reduce diearea. For example, in a non-uniform segmented channel array, if a signalhas to travel a track distance comprising a certain predetermined tracklength, it is more likely that that track length can be closely matchedin a non-uniform segmented channel array due to the variety of tracklengths and combinations of track lengths to choose from.

The problems associated with non-uniform segmented channel arrayarchitecture arise from a design and verification viewpoint. As is wellknown to those skilled in the art of integrated circuit design,non-uniform channel array architectures do not lend themselves tomodular design. Modular design of integrated circuits involves thedesigning one portion of the circuit as a small block. The small blockis then stepped and repeated across the entire chip. This procedure isknown in the art as tiling.

Non-uniform segmented channel array architectures do not lend themselvesto modular design due to the unique nature of each non-uniform tracksegment. Because of this various problems arise when designing anon-uniform segmented channel array. For example, the circuit design ofeach channel has to be drawn manually for the entire length of the chip.The same circuit design has to be repeated in the software devicedescription. In addition, arrays with non-uniform segmented channels intwo dimensions (i.e. horizontal and vertical) have a unique circuitdesign at each intersection of a horizontal channel and vertical channelin the array. Thus, the mask design and layout has to be repeated forevery unique intersection of channels, the number of which tends to growas the product of the number of channels in each direction grows.

Further, non-uniform segmented channel array architectures greatlyincrease the complexity of the verification problem. For example, theeffort required to verify the circuit design against the architecture,the mask design against the circuit design, the software design againstthe architecture, etc., is proportional to the number of channelintersections in the array. Manual inspection of each channel trackaddressing signal and programmable element locations is already errorprone and is amplified in the case of non-uniform segmented channelarray architectures due to having to check the entire circuit ratherthan a block that has been repeated throughout the circuit.

Thus, there is a need in the art for a non-uniform segmented channelarray architecture that can be designed as a block that may be steppedand repeated to build an entire chip. There is also a need in the artfor a non-uniform segmented channel array block, i.e. circuit design,mask design, layout and software device description, that need bedesigned only once.

SUMMARY OF THE SYSTEM

The presently disclosed system is an apparatus comprising a non-uniformsegmented channel array that is generated by the repetition of a singleblock. The apparatus comprises a repeatable non-uniform segmentedrouting architecture in a field programmable gate array having aplurality of sets of routing tracks having a first and last trackposition proceeding in a first direction and having at least oneprogrammable element and at least one direct address device. The tracksare partitioned into uniform lengths and a track in the last positioncrosses over to a track in the first position immediately prior to saidpartition. The apparatus of the present system also has a plurality ofsets of routing tracks having a first and last track position proceedingin a second direction. The tracks proceeding in the second directionhave at least one programmable element and direct address device,wherein the tracks are partitioned into non-uniform lengths and saidlast track position crosses over to a first track position immediatelyprior to said partition.

The above-described block is repeatable due to the twisting (or crossingover) of tracks. The abutment of a number of these repeatable blocksgenerates a routing channel and generating the repetition of the blocksin both dimensions generates a fully segmented-channel routing array.

A better understanding of the features and advantages of the presentinvention will be obtained by reference to the following detaileddescription of the invention and accompanying drawings which set forthan illustrative embodiment in which the principles of the invention areutilized.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified block diagram of an FPGA core tile 100incorporating the non-uniform segmented routing channel architecture(not shown), as disclosed in the present system.

FIG. 2 is a block diagram of an illustrative FPGA including multiplecore tiles 100 as shown as an example in FIG. 1.

FIG. 3 is a simplified schematic diagram illustrating the horizontalsegmentation pattern between logic cluster columns.

FIG. 4 is a simplified schematic diagram illustrating the horizontalsegmentation pattern between a logic cluster column and an input/outputcluster.

FIG. 5 is a simplified schematic diagram illustrating the verticalsegmentation pattern for every two logic cluster rows.

FIG. 6 is a simplified schematic diagram illustrating the verticalsegmentation pattern between a logic cluster column and an input/outputcluster as shown in FIGS. 1 and 2.

DETAILED DESCRIPTION OF THE DRAWINGS

Those of ordinary skill in the art will realize that the followingdescription of the present invention is illustrative only and not in anyway limiting. Other embodiments of the invention will readily suggestthemselves to such skilled persons.

The present invention discloses a device and a method of producingnon-uniform segmented channel array architectures that can be steppedand repeated to build an entire FPGA circuit. The horizontal andvertical tracks are segmented within a core tile 100 and between coretiles 100 as set forth in FIG. 1 and in greater detail below.

In this application, a track refers to a track that spans the entirechip. For example, a track spans the entire chip, and thus all tracklengths are the same. Track segments are portions of the track that arebroken via programmable elements into different segment lengths. It isthe length of the track segments that are affected by the segmentation.

In this application, non-uniform track segmentation provides both adistribution of segment lengths and a distribution of segment offsets(i.e. starting points). This is because the signals being routed in achannel not only travel different distances but also start at differentpoints, as discussed in greater detail below. The segmentation isnon-uniform is both these respects.

FIG. 1 is a simplified block diagram of an FPGA 10 having one core tile100 incorporating the non-uniform segmented routing channel architecture(not shown), as disclosed in the present system. As shown in FIG. 1,core tile 100 comprises an array of logic clusters 110, a column ofrouted clock clusters 112, a row of hard-wired clock clusters 114, aclock tile cluster 116, a row of RAM clusters 108, RAM memory 106. FPGAcore tile 100 is surrounded by two rows of input/output (I/O) clusters104 and I/O banks 102. In FIG. 1, edges of the device shown are referredto in terms of compass directions, for example, the top edge isdesignated the “north” side of the device. On the north and south edgessurrounding FPGA core tile 100 there are eight phase-locked-loopclusters (PLL clusters) 120.

FIG. 2 is a block diagram of an illustrative FPGA 10 including multiplecore tiles 100 as shown as an example in FIG. 1. As shown in FIG. 2,FPGA device comprises four core tiles 100, though other numbers of tilesare possible. Core tiles 100 are surrounded by I/O clusters 104 and I/Obanks 102.

The term track refers to a signal routing line that runs the distance ofthe FPGA. The term “segment” refers to a portion of the track. Eachsegment of a track is coupled to the next adjacent segment by aprogrammable element. If the programmable elements are programmed, thesegments are electrically connected. In this application, theprogrammable elements defining each segment of are referred to as“offsets” or starting points of a segment. The term “segmentationpattern group” refers to a horizontal track segment length as wide as alogic cluster or a vertical track segment that equals two logic clusterrows as illustrated in FIG. 1. The segmentation pattern groups repeat inpatterns as set forth below.

FIG. 3 is a simplified schematic diagram illustrating the horizontalsegmentation pattern 200 between logic cluster 110 columns. Non-uniformsegmented horizontal channel 200 comprises 50 tracks (HT0-HT49) dividedinto horizontal channel groups 202, 204, 206, 208, 210, 212, 214, 216.As set forth above, each horizontal segmentation pattern group is into alength as wide as a logic cluster 110 columns. The horizontal channelgroups each independently generate a distinct set of track segments witha given segmentation. The groups are assembled together to create arouting channel with the desired number of tracks and the desiredtrack-segment lengths and offsets.

Horizontal channel group 202 comprises three tracks HT49, HT48 and HT47.Tracks HT49 and HT48 each have a direct address device 220 and aprogrammable element 218. For illustrative purposes only and in no waymeant to limit the present disclosure, in this example programmableelement 218 comprises an antifuse and direct address devices 220 maycomprise pass transistors. As is well known to those of ordinary skillin the art, direct address devices are employed to program acorresponding programmable element when a programmable element is to beprogrammed. Programmable elements 218 are the offsets or starting pointsof the next segments in tracks HT49 and HT48 and for all other tracks inhorizontal segmentation pattern 200. Offsets enable greater flexibilityin the circuit given that a signal may traverse horizontal and/orvertical track via any starting point as well as traveling differentdistances via the varying length track segments.

Track HT47 has two direct address devices 220 and two programmableelements 218. At one end of horizontal channel group 202 there is across-over 222 immediately before the horizontal channel group 202segment repeats wherein track position HT47 crosses-over to trackposition HT49. At the next segment repetition, track position HT48 willcrossover to track position HT49 (formerly track HT47). Horizontaltracks HT47-HT49 and all the tracks (horizontal and vertical) discussedbelow lay on the same layer on the die. The crossover is accomplished bylaying the last track (or wire) over the first number of wires so thatthe last wire becomes the first. In effect, the crossover produces atwist of the wires.

The result of repeating horizontal channel group 202 is that each tracksegment has a unit length of one and then a unit length of two and anoffset at track segment lengths of one and two and repeats in thispattern producing non-uniform track segments. The unit lengths, forpurposes of example only, in this embodiment are equal to a tracksegment length. Thus, a repeating uniform segment results in anon-uniform segmented track. This will be discussed in greater detailbelow.

In another illustrative example, horizontal channel group 204 comprisesfive tracks HT46, HT45, HT44, HT43 and HT42. Tracks HT46, HT45, HT44 andHT42 each have a direct address device 220 and a programmable element218. As set forth above in this example programmable element 218 is anantifuse. Track HT44 has a direct address device 220. Track HT43 has aprogrammable element 218. At one end of horizontal channel group 204there is a crossover 222 just before the horizontal channel group 204segment repeats wherein track position HT42 crosses over to trackposition HT46. At the next segment repetition, track position HT43 willcrossover to track position HT46 (formerly track position HT42). Theresult of repeating horizontal channel group 204 is that each tracksegment has a unit length of two and then a unit length of three andoffsets at track segment unit lengths of two and three and repeats inthis pattern. Thus, each track ends up having different segment lengthsand offset points even though the same block is being stepped andrepeated to produce the array.

Horizontal channel group 206 comprises four tracks HT41, HT40, HT39 andHT38. Tracks HT41 and HT39 each have a direct address device 220 and aprogrammable element 218. Tracks HT40 and HT38 do not have a directaddress device or a programmable element. At one end of horizontalchannel group 206 there is a cross-over 222 just before the horizontalchannel group 206 segment repeats wherein track position HT38crosses-over to track position HT41. At the next segment repetition,track position HT39 crosses-over to track position HT41 (formerly trackposition HT38). The result of repeating horizontal channel group 206 isthat each track segment has a unit length of three and then a unitlength of five and offsets at track segment unit lengths of three andfive and repeats in this pattern. Thus, each track ends up havingdifferent segment lengths and offset points even though the same blockis being stepped and repeated to produce the array.

Horizontal channel group 208 comprises four tracks HT37, HT36, HT35 andHT34. Tracks HT37 and HT35 each have a direct address device 220 and aprogrammable element 218. Tracks HT40 and HT38 do not have a directaddress device or a programmable element. At one end of horizontalchannel group 208 there is a cross-over 222 just before the horizontalchannel group 208 segment repeats wherein track position HT34 crossesover to track position HT37. At the next segment repetition, trackposition HT35 crosses over to track position HT37 (formerly trackposition HT34). The result of repeating horizontal channel group 208 isthat each track segment has a unit length of four and an offset at tracksegment length of four and repeats in this pattern.

Horizontal channel group 210 comprises five tracks HT33, HT32, HT31,HT30 and HT29. Track HT31 has a direct address device 220 and aprogrammable element 218. Track HT33 has a programmable element 218.Track HT29 has a direct address device 220. Tracks HT30 and HT32 do nothave a direct address device or a programmable element. At one end ofhorizontal channel group 210 there is a cross-over 222 just before thehorizontal channel group 210 segment repeats wherein track position HT29crosses-over to track position HT33. At the next segment repetition,track position HT30 crosses-over to track position HT33 (formerly trackposition HT29). The result of repeating horizontal channel group 210 isthat each track segment has a unit length of four and then a unit lengthof six and an offset at track segment unit length of four and six andrepeats in this pattern. Thus, each track ends up having differentsegment lengths and offset points even though the same block is beingstepped and repeated to produce the array.

Horizontal channel group 212 comprises six tracks HT28, HT27, HT26,HT25, HT24 and HT23. Tracks HT28 and HT25 each have a programmableelement 218. Tracks HT26 and HT23 each have a direct address device 220.At one end of horizontal channel group 212 there is a cross-over 222just before the horizontal channel group 212 segment repeats whereintrack position HT23 crosses-over to track position HT28. At the nextsegment repetition, track position HT24 crosses-over to track positionHT28 (formerly track position HT23). The result of repeating horizontalchannel group 212 is that each track segment has a unit length of fiveand then a unit length of seven and an offset at track segment unitlength of five and seven and repeats in this pattern. Thus, each tracksegment ends up having different segment lengths and offset points eventhough the same block is being stepped and repeated to produce thearray.

Horizontal channel group 214 comprises ten tracks HT22, HT21, HT20,HT19, HT18, HT17, HT16, HT15, HT14 and HT13. Tracks HT19, HT16 and HT13each have a direct address device 220. Tracks HT22 and HT18 has aprogrammable element. At one end of horizontal channel group 214 thereis a cross-over 222 just before the horizontal channel group 214 segmentrepeats wherein track position HT13 crosses-over to track position HT22.At the next segment repetition, track position HT14 crosses-over totrack position HT22 (formerly track position HT13). The result ofrepeating horizontal channel group 214 is that each track segment has aunit length of eight and then a unit length of twelve and offsets attrack segment unit lengths of eight and twelve and repeats in thispattern. Thus, each track ends up having different segment lengths andoffset points even though the same block is being stepped and repeatedto produce the array.

Finally, horizontal channel group 216 comprises thirteen tracks HT12,HT11, HT10, HT9, HT8, HT7, HT6, HT5, HT4, HT3, HT2, HT1 and HT0. TracksHT9, HT5 and HT1 each have a direct address device 220. Track HT12 has aprogrammable element. At one end of horizontal channel group 216 thereis a cross-over 222 just before the horizontal channel group 216 segmentrepeats wherein track position HT0 crosses-over to track position HT12.At the next segment repetition, track position HT1 crosses-over to trackposition HT12 (formerly track position HT0). The result of repeatinghorizontal channel group 216 is that each track segment has a unitlength of twenty-six and an offset at a track segment unit length oftwenty-six and repeats in this pattern.

As those skilled in the art having the benefit of this disclosure willreadily recognize, the above examples are illustrative only and are inno meant to limit the present invention. As is obvious from the presentdisclosure, one could vary the number and location of programmableelements 218 and direct address devices 220 to vary the length of any ofthe track segments and the location of offsets in any given set or setsof channel groups. As also is apparent to those of ordinary skill in theart, the assignment of programmable elements, in this example antifuses,to either the right or left columns of the repeatable blocks will ingeneral affect the track segment lengths that result. Also, the numberof tracks in a “channel group” will also affect the length of the tracksegments.

FIG. 4 is a simplified schematic diagram illustrating the horizontalsegmentation pattern 300 between logic cluster 110 column andinput/output cluster 104 as shown in FIGS. 1 and 2. Non-uniformhorizontal channel 300 comprises 50 tracks (HT0-HT49) divided intohorizontal channel groups 302, 304, 306, 308, 310, 312, and 314, 316.Non-uniform horizontal channel extends directly into the input/outputcluster 104 columns. As shown in FIG. 4, there is no furthersegmentation through programmable elements. Horizontal channel groups314 and 316 contain direct address devices 320 on tracks HT22, HT16,HT13, HT12, HT8, HT6, HT4, HT2. As set forth previously, direct addressdevices may comprise pass transistors. Horizontal channel groups 314 and316 contain direct address devices 320 because the track lengths exceeda certain maximum number of unit lengths from the last direct addressdevice 320 from inside core tile 100. In the present example, themaximum length equals five track lengths.

FIG. 5 is a simplified schematic diagram illustrating the verticalsegmentation pattern 400 for every two logic cluster 110 rows.Non-uniform segmented vertical channel 400 comprises 58 tracks(VT0-VT57) divided into vertical channel groups 402, 404, 406, 408, 410,412, and 414. Each vertical segmentation pattern group is equal to twologic cluster 110 rows. As would be readily apparent to one skilled inthe art having the benefit of this disclosure, the vertical segmentchannel length may be varied according to the requirements necessitatedby the circuit design.

Vertical channel group 402 comprises three tracks VT57, VT56 and VT55.Track VT57 and VT56 each have a direct address device 420 and aprogrammable element 418. In this example, programmable element 418 isan antifuse and direct address device may comprise a pass transistor.Track VT55 has two direct address devices 420 and two programmableelements 418. At one end of vertical channel group 402 there is across-over 422 just before the vertical channel group 402 segmentrepeats wherein track position VT55 crosses-over to track position VT57.At the next segment repetition, track position VT56 crosses-over totrack position VT57 (formerly track position VT55). The result ofrepeating vertical channel group 402 is that each track segment has aunit length of one and then a unit length of two and an offset at tracksegment unit length of one and two and repeats in this pattern. Thus, arepeating uniform segment results in a non-uniform segmented track. Thiswill be discussed in greater detail below. Thus, each track ends uphaving different segment lengths and offset points even though the sameblock is being stepped and repeated to produce the array.

In another illustrative example, vertical channel group 404 comprisesfive tracks VT54, VT53, VT52, VT51 and VT50. Tracks VT54, VT53, VT51 andVT50 each have a direct address device 420 and a programmable element418. As set forth above, in this example programmable element 418 is anantifuse. Track HT52 does not have a programmable element 418 or adirect address device. At one end of vertical channel group 404 there isa cross-over 422 just before the vertical channel group 404 segmentrepeats wherein track position VT50 crosses-over to track position VT54.At the next segment repetition, track position VT51 crosses-over totrack position VT54 (formerly track position VT50). The result ofrepeating vertical channel group 404 is that each track segment has aunit length of two and then a unit length of three and offsets at tracksegment unit lengths two and three and repeats in this pattern. Thus,each track ends up having different segment lengths and offset pointseven though the same block is being stepped and repeated to produce thearray.

Vertical channel group 406 comprises seven tracks VT49, VT48, VT47,VT46, VT45, VT44, and VT43. Tracks VT47 and VT43 each have a directaddress device 420. Tracks VT49 and VT46 each have a programmableelement 418. At one end of vertical channel group 406 there is across-over 422 just before the vertical channel group 406 segmentrepeats wherein track position VT43 crosses-over to track position VT49.At the next segment repetition, track position VT44 crosses-over totrack position VT49 (formerly track position VT43). The result ofrepeating vertical channel group 406 is that each track segment has aunit length of six and then a unit length of eight and offsets at tracksegment unit lengths six and eight and repeats in this pattern. Thus,each track ends up having different segment lengths and offset pointseven though the same block is being stepped and repeated to produce thearray.

Vertical channel group 408 comprises fourteen tracks VT42, VT41, VT40,VT39, VT38, VT37, VT36, VT35, VT34, VT33, VT32, VT31, VT30 and VT29.Tracks VT39, VT34 and VT30 each have a direct address device 420. TrackVT42 has a programmable element 418. At one end of vertical channelgroup 408 there is a cross-over 422 just before the vertical channelgroup 408 segment repeats wherein track position VT29 crosses-over totrack position VT42. At the next segment repetition, track VT30crosses-over to track position VT42 (formerly track position VT29). Theresult of repeating vertical channel group 408 is that each tracksegment has a unit length of twenty-eight and an offset at a tracksegment length twenty-eight and repeats in this pattern.

Vertical channel group 410 comprises nine tracks VT28, VT27, VT26, VT25,VT24, VT23, VT22, VT21 and VT20. Tracks VT27 and VT23 each have a directaddress device 420. Track VT20 has a programmable element 418. At oneend of vertical channel group 410 there is a cross-over 422 just beforethe vertical channel group 410 segment repeats wherein track positionVT28 crosses-over to track position VT20. At the next segmentrepetition, track position VT27 crosses-over to track position VT20(formerly track position VT28). The result of repeating vertical channelgroup 410 is that each track segment has a unit length of eighteen andan offset at a track segment length of eighteen and repeats in thispattern.

Vertical channel group 412 comprises eleven tracks VT19, VT18, VT17,VT16, VT15, VT14, VT13, VT12, VT11, VT10 and VT9. Tracks VT19, VT16 andVT12 each have a direct address device 420. Tracks VT14 and VT9 eachhave a programmable element 418. At one end of vertical channel group412 there is a cross-over 422 just before the vertical channel group 412segment repeats wherein track position VT19 crosses-over to trackposition VT9. At the next segment repetition, track position VT18crosses-over to track position VT9 (formerly track position VT19). Theresult of repeating vertical channel group 412 is that each tracksegment has a unit length of ten and then a unit length of twelve andoffsets at track segment unit lengths of ten and twelve and repeats inthis pattern. Thus, each track ends up having different segment lengthsand offset points even though the same block is being stepped andrepeated to produce the array.

Vertical channel group 414 comprises nine tracks VT8, VT7, VT6, VT5,VT4, VT3, VT2, VT1 and VT0. Tracks VT6 and VT4 each have a directaddress device 420. Tracks VT7 and VT5 each have a programmable element418. Tracks VT2 and VT0 each have both a direct address device 420 and aprogrammable element 418. At one end of vertical channel group 414 thereis a cross-over 422 just before the vertical channel group 414 segmentrepeats wherein track position VT8 crosses-over to track position VT0.At the next segment repetition, track position VT7 crosses-over to trackposition VT0 (formerly track position VT8). The result of repeatingvertical channel group 414 is that each track has a unit length of fourand then a unit length of five and offsets at track segment unit lengthsof four and five and repeats in this pattern. Thus, each track ends uphaving different segment lengths and offset points even though the sameblock is being stepped and repeated to produce the array.

FIG. 6 is a simplified schematic diagram illustrating the verticalsegmentation pattern 600 between logic cluster 110 column andinput/output cluster 104 as shown in FIGS. 1 and 2. Non-uniform verticalchannel 600 comprises 58 tracks (VT0-VT57) divided into vertical channelgroups 602, 604, 606, 608, 610, 612, 614. Non-uniform vertical channelextends directly into the input/output cluster 104 columns. As shown inFIG. 4, there is no further segmentation through programmable elements.Vertical channel groups 606, 608, 610 and 612 contain direct addressdevices 620 on tracks VT46, VT42, VT37, VT36, VT33, VT32, VT26, VT24,VT20, VT19, VT16 and VT9. As set forth previously, direct addressdevices may comprise pass transistors. Vertical channel groups 606, 608,610 and 612 contain direct address devices 620 because the track segmentlengths exceed a certain number of unit lengths from the last directaddress device 620 from inside core tile 100. In the present example,the unit length equals five from the last direct address device 620 frominside core tile 100.

The non-uniform segmented channel array of the present system provides avariety of track-segment lengths and offsets, and thus is more flexibleand faster than a device having a uniform segmented channel array. Forexample, in the present non-uniform segmented channel array, if a signalhas to travel a track distance comprising a certain predetermined tracklength and starting from a certain predetermined position, it is morelikely that that track length and offset (starting position) can beclosely matched in a non-uniform segmented channel array due to thevariety of track segment lengths and offsets to choose from. Inaddition, the uniform-segment blocks of the present system can bestepped and repeated to produce a non-uniform segmented channel array.

It should be understood that various alternatives to the embodiments ofthe disclosed method and apparatus described herein might be employed inpracticing the disclosed method and using the disclosed apparatus. It isintended that the following claims define the scope of the disclosedmethod and apparatus and that methods and structures within the scope ofthese claims and their equivalents be covered thereby.

1. A repeatable non-uniform segmented routing architecture in a fieldprogrammable gate array comprising: a repeatable block of routingtracks, the routing tracks grouped into sets of routing tracks, each sethaving a first routing track in a first track position, a second routingtrack in a last track position, a programmable element, and a directaddress device for programming said programmable element; wherein atleast one of said routing tracks is segmented into non-uniform lengthsby said programmable element and said second routing track crosses-overto said first track position in a region adjacent to an edge of saidrepeatable block; and wherein a first plurality of said routing tracksets proceed in a horizontal direction and a second plurality of saidrouting track sets proceed in a vertical direction.